The present application relates to systems and methods for probing features and functions of semiconductor integrated circuits (ICs).
To improve IC functionality and performance, IC manufacturers in the last four decades have been shrinking the sizes of circuit components, and at the same time, increasing the number of circuit components per IC. As electronic devices become more miniaturized and more powerful, IC devices become smaller and more devices are packed onto each chip. The cost of manufacturing has increased and the yield has decreased for these devices. New causes of yield decrease emerge as different materials are utilized and the process variation tolerances shrink.
Probe tools are frequently utilized during the testing and debugging of IC designs, where efforts are focused on defect localization and accurate waveform and timing measurements of signal switching inside silicon-based devices. Both signal measurements and optical analysis with probe tools are performed through the back side of the device. By utilizing the optics in the probe tool, electrical properties of the extremely small individual components (i.e. transistors) on the IC can be measured for proper functionality without interfering with the devices' function.
The decreasing sizes of circuit features in electronic devices create a significant challenge for probe tools. Analytical tools are required to discern increasingly smaller circuit features and to preform timing analysis on single transistor nodes. One requirement for the probing systems is to provide optical measurement at different magnifications, including high resolution measurement by high numerical aperture (N.A.) solid immersion lens (SIL). Another challenge for the probing systems is to suppress measurement errors caused by mechanical disturbances. Moreover, a significant amount of heat can be generated by operating the device at design speeds and voltages during optical measurements, and the light source from the probing tool can also generate heat when focused onto an IC device, both of which can affect the proper function of the integrated circuit. As such another challenge for probing systems is to remove the increasing amount of heat generated during the debug and test procedures.
Accordingly, there is a need for improved optical probe systems that can meet the challenges and requirements presented by the sophisticated and evolving semiconductor industry.